Question

The radius of curvature of a concave mirror is 30cm. What is the focal length of this mirror.

Answer 1

Answer:

15cm

Explanation:

According to the formula

=>R=2f

=> 30/2=15

Hence , the focal length is 15 cm

Answer 2

Question :-

The radius of curvature of a concave mirror is 30cm. What is the focal length of this mirror.

Given :-

Radius of curvature of a concave mirror = 30cm

To find :-

The focal length of the mirror.

Formula used :-

Radius of curavature(R) = 2 × focal length (f)

R = 2f

Solution :-

Radius of curvature of a concave mirror = -30cm

Focal length of the mirror (f) = ?

We know that,

$\implies\bf R = 2f$

$\implies\bf f = \dfrac{R}{2}$

$\implies\bf f = \dfrac{-30}{2}$

$\implies\bf f = -15cm$

Therefore,

Focal length of concave mirror = -15cm

More to know :-

Spherical Mirror :- A spherical mirror is a part of hollow sphere whose one surface is polished and the other is reflecting.

Concave mirror :- Concave mirror is one which is silvered from outer side and reflection takes place at inner side.